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RAS Technologies and their commercial applicationfinal report Stirling Aquaculture Page i

Review of Recirculation Aquaculture System

Technologies and their Commercial Application

Prepared for Highlands and Islands Enterprise

Final Report March 2014

Stirling AquacultureInstitute of Aquaculture

University of StirlingStirling FK9 4LA

Tel: +44 (0)1786 466575Fax: +44 (0)1786 462133

E-mail: [email protected]:www.stirlingaqua.com

In Association with RAS Aquaculture Research Ltd.
http://www.stirlingaqua.com/http://www.stirlingaqua.com/http://www.stirlingaqua.com/http://www.stirlingaqua.com/


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RAS Technologies and their commercial applicationfinal report Stirling Aquaculture Page ii

Report authors:Francis Murray, John Bostock (University of Stirling) and David Fletcher (RAS AquacultureResearch Ltd.)

Disclaimer: The contents of this report reflect the knowledge and opinions of the report authors at the time of

writing. Nothing in the report should be construed to be the official opinion of the University of Stirling or Highlands and

Islands Enterprise. The report is intended to be a general review of recirculated aquaculture systems technologies andtheir potential impact on the Scottish aquaculture sector. No part of the report should be taken as advice either for or

against investment in any aspect of the sector. In this case, independent expert advice that examines specific proposals

on their own merits is strongly recommended. The report authors, the University of Stirling, RAS Aquaculture Research

Ltd. and Highlands and Islands Enterprise accept no liability for any use that is made of the information in this report.

Whilst due care has been taken in the collation, selection and presentation of information in the report, no warranty is

given as to its completeness, accuracy or future validity.

Copyright: The copyright holder for this report is Highlands and Islands Enterprise other than forphotographs or diagrams where copyright may be held by third parties. No use or reproduction forcommercial purposes are allowed.


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Contents

1 Introduction ............................................................................................................................................................................ 11.1 Background ...................................................................................................................................................................... 11.2 Objectives ......................................................................................................................................................................... 2

1.3 Approach .......................................................................................................................................................................... 22 Historic development of RAS technologies .................................................................................................................... 32.1 Origins ............................................................................................................................................................................... 32.2 Commercial RAS performance in the UK ............................................................................................................... 42.3 Other regional commercial RAS Examples ........................................................................................................... 10

3 RAS technology and range of application ...................................................................................................................... 133.1 Rationale for RAS ......................................................................................................................................................... 13

3.1.1 RAS Advantages ................................................................................................................................................. 133.1.2 Challenges of RAS technology ....................................................................................................................... 14

3.2 RAS typology and design considerations ................................................................................................................ 163.3 Current examples ........................................................................................................................................................ 19

3.4 Biosecurity and disease issues in RAS ..................................................................................................................... 223.4.1 General issues and approaches to biosecurity .......................................................................................... 223.4.2 Parasites in RAS ................................................................................................................................................. 243.4.3 Harmful Algal Blooms (HABs) in RAS ......................................................................................................... 243.4.4 Microbial pathogens .......................................................................................................................................... 253.4.5 Use of Chemical Therapeutants in RAS ...................................................................................................... 253.4.6 Alternative Treatments.................................................................................................................................... 263.4.7 Non-chemical Control of Disease ................................................................................................................ 27

3.5 Developing technologies ................ ................. ................ ................ ................. ................ ................. ................ .......... 283.5.1 Diet density manipulation ............................................................................................................................... 283.5.2 Tank self-cleaning technology ........................................................................................................................ 283.5.3 Nitrate denitrification in RAS ......................................................................................................................... 283.5.4 Annamox systems ............................................................................................................................................. 303.5.5 Automated in-line water quality monitoring .............................................................................................. 313.5.6 Tainting substances: Geosmins (GSM) and 2-methylisorboneol (MIB) contamination ofaquaculture water ................................................................................................................................................................ 313.5.7 Efficient control of dissolved gases ............................................................................................................... 333.5.8 Use of GMOs ..................................................................................................................................................... 33

4 Prospects for salmon farming in RAS operations ........................................................................................................ 354.1 Background .................................................................................................................................................................... 354.2 Current activity ............................................................................................................................................................. 35

4.3 Intermediate strategies ............................................................................................................................................... 374.4 Technical issues for salmon production in RAS ................................................................................................... 404.5 Economic appraisals and prospects ......................................................................................................................... 41

5 Potential for commercial RAS in HIE area .................................................................................................................... 445.1 Candidate species and technologies ........................................................................................................................ 445.2 Competitive environment .......................................................................................................................................... 465.3 Economic appraisal ................ ................ ................ ................ ................. ................ ................. ................ ................ ..... 46

5.3.1 Economics of RAS Production of Atlantic Salmon ................................................................................... 465.3.2 Economics of RAS production of other species ....................................................................................... 50

6 Implications for HIE area if RAS develop elsewhere .................................................................................................. 546.1 Potential scenarios ....................................................................................................................................................... 54

6.2 Market factors ............................................................................................................................................................... 54


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6.3 Economic impacts ............... ................. ............... ................. ................ ................. ................ ................ ................ ........ 577 Conclusions ........................................................................................................................................................................... 61

7.1 Summary of findings ..................................................................................................................................................... 617.2 Recommendations ........................................................................................................................................................ 63

References ...................................................................................................................................................................................... 65

Annex 1: Example RAS technology suppliers


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RAS Technologies and their commercial applicationfinal report Stirling Aquaculture Page v

Review of Recirculation Aquaculture System

Technologies and their Commercial Application

EXECUTIVE SUMMARY

Recirculation aquaculture systems (RAS) are designed to minimise water consumption, control cultureconditions and allow waste streams to be fully managed. They can also provide some degree of biosecuritythrough measures to isolate the stock from the external environment. RAS technology has steadily developedover the past 30 years and is widely used for broodstock management, in hatcheries and increasingly forsalmon smolt production. By comparison, the progress of RAS for grow-out to market size products has beenmore restricted and there is a substantial track record of company failures both in the UK, Europe andinternationally. The reasons for this are varied, but include challenges of economic viability and operatingsystems at commercial scales.

In spite of this history, several technology companies present a hard sales pitch and claim to have successfullydelivered numerous commercial RAS farms targeting a range of species, when in reality the farms may haveceased to exist or production levels are quite insignificant (


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The benefits of RAS, as an alternative to cage production of salmon, needs to be assessed based on businesseconomics while also taking into account the social and broad environmental (rather than selective) impact ofboth production methods. If the UK is to increase its sustainable seafood supplies it might consider utilisingRAS technology to substitute some of the overseas imports rather than challenging another UK productionmethod to produce the same species. If cage and RAS production technologies try to out-compete each otheron sustainability criteria then imported seafood, with unknown environmental credentials, will likely be the

winner.

Drawing on the lessons from previous ventures, RAS businesses should not be overly dependent on expectedprice premiums since these may only be secured for a small fraction of the production. This premium marketmight weaken as increased RAS production develops close to the main markets within the UK or abroad.

Considering energy use is a major factor in RAS, investors promoting RAS technology for commodity specieslike salmon might sensibly focus on securing a significant contribution to their energy supplies from sustainablesources to prove their environmental credentials. Scotland might be strategically better placed than otherareas to address this objective.

RAS farms are able to better manage effluent waste and this is a key argument in the favour of this productiontechnology. Irrespective of whether the farm is marine or freshwater the waste has a real economic value andan increasing range of recycling options is available. However, RAS investors rarely present properlyresearched plans and investment for utilisation of farm waste which quickly becomes a management problemas production expands.

While RAS technology has advanced significantly in recent years there remain several water quality treatmentand effluent management issues which remain incompletely understood. These particularly refer to RAS farmsusing >90% water recirculation (< 10% replacement per day) which is really the minimal level required forefficient operation. Equally, the technology available for monitoring the number and range of RAS water qualityparameters in real time requires significant improvement

RAS technology is developing and new water treatment processes are being tested, particularly with respectto dissolved nitrogen, carbon dioxide and organic taint compounds. Properly designed and managed RAS areincreasingly commercially viable for high unit value species or life stages. The economic bar to the use of RASwill gradually be lowered as technology improves and energy and other efficiencies are realised. This is likely toinclude some scale economies both in capital and operating costs, although for the present, system design andlocation appear to be more important.

The use of RAS technology is already increasing in the Scottish salmon industry and further investment in thisarea will almost certainly be essential for the successful future of the industry. There is a long-term threat to

the industry from RAS technology being adopted closer to major markets, but this should be seen as anincentive to continue to innovate for cost competitiveness and diversification using the natural resourcesavailable in Scotland.


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RAS Technologies and their commercial applicationfinal report Stirling Aquaculture Page 1

1 Introduction

1.1 Background

Recirculating Aquaculture Systems (RAS) are intensive, usually indoor tank-based systems that achieve highrates of water re-use by mechanical, biological chemical filtration and other treatment steps. Preciseenvironmental control means aquatic species can be cultured out with their normal climatic range, allowingoperators to prioritise production goals linked to market, regulatory or resource availability criteria. Forexample RAS technology can be useful where ideal sites are unavailable e.g. land or water space is limiting,where water is in short supply or of poor quality, if temperatures are outside the optimum species range or ifthe species is exotic. It can also be employed when environmental regulation demands greater control ofeffluent streams and biosecurity (exclusion of pathogens and/or retention of germplasm) or where low-costforms of energy are available. The ability to maintain optimal and constant water quality conditions can alsobring animal welfare gains. Market benefits include increased ability to match seasonal supply and demand, toco-locate production with consumer/processing centres and linked to this improved traceability and consumer

trust.

RAS culture is also compatible with many contemporary goals for sustainable aquaculture including the EUstrategy for sustainable aquaculture 20091. Many environmental groups support RAS over open-productionsystems (e.g. marine or freshwater cage production) for the same reasons. Other proponents includeproviders of equipment and technical services including universities with research and extension programsfocusing on RAS. Others attribute biosecurity and potential food-safety benefits to RAS2.

However investors in commercial RAS still face many challenges. High initial investment and operational costsmake operations highly sensitive to market price and input costs (especially for feed and energy). As table-fishtend to have lower unit value compared to juvenile life-stages (e.g. smolts) or products such as sturgeoncaviar, their profitable production requires much higher operational carrying capacities. Despite ongoingtechnological improvement, at these production levels challenges linked to filtration inefficiencies andassociated chronic sub-lethal effects of metabolic wastes (NH4, NO2and CO2) remain key design challenges.Consequently table-fish production in RAS still represents a high risk investment evidenced by their poor long-term track record for lenders.

RAS systems are commonly characterised in terms of daily water replacement ratio (% system volumereplaced by fresh water over every 24 hours) or recycle ratios (% total effluent water flow treated andreturned for reuse per cycle). For a fixed water supply, increasing recycle ratios above 0% (open-flow)corresponds with an exponential increase in production capacity with greatest gains achieved at rates above

90%. By convention intensive or fully-recirculating RAS are typically defined as systems with replacementratios of less than 10% per day. Conversely systems with higher replacement rates can be characterised aspartial-replacementsystems. Partial replacement is commonly used to intensify rainbow trout production inraceways and tanks. Such systems require limited, often modular water-treatment installations and thereforemuch lower levels of capital investment compared to intensive-RAS. Management goals are also likely to differ;partial-replacement may be most appropriate where water availability or discharge consents are limitingwhereas intensive-RAS offer greater scope for heat retention for accelerated growth, biosecurity andlocational freedom. For these reasons intensive RAS are also more likely to be established as fully containedindoor systems. As experience has demonstrated, pumping costs are generally likely to be prohibitive for

1"Building a sustainable future for aquaculture, A new impetus for the Strategy for the Sustainable Development of European Aquaculture"2 SUSTAINAQhttp://ec.europa.eu/research/biosociety/food_quality/projects/181_en.html
http://ec.europa.eu/research/biosociety/food_quality/projects/181_en.htmlhttp://ec.europa.eu/research/biosociety/food_quality/projects/181_en.htmlhttp://ec.europa.eu/research/biosociety/food_quality/projects/181_en.htmlhttp://ec.europa.eu/research/biosociety/food_quality/projects/181_en.html


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partially recirculating, pump-ashore salmon systems, the scope of this report is limited to intensive fully-recirculating RAS options (whilst observing that increasing environmental regulatory pressure is also drivingprogressive intensification of existing flow-through systems).

1.2 Objectives

The content of the study is set out in the terms of reference as follows:

Historic development of RAS technologies Description of current range and variety of RAS operations Appraisal of short to medium term prospects of commercial viability of RAS operations for

production of Atlantic salmon for the table Appraisal of short to medium term prospects for commercially viable operation of RAS in the HIE

area producing one or more species (fin fish, shellfish, algae etc.) Appraisal of short to medium term implications for the HIE area in scenarios where commercially

viable RAS operations are established in the UK and/or overseas.

1.3 Approach

The report was based on

- A review of secondary literature- telephone survey of key informants associated with the salmon and RAS sectors (Table 1)- Case study research based on documentation and interviews with those directly involved with recent

as well as failed historic start-ups- The authors direct experience of commercial culture of various species in RAS

Table 1: Summary of key informants by specialisation and species of interest

Specialisation Location Species No RespondentsAquaculture RAS insurance under-writer International Salt& fresh water 1

RAS owner/operators UK & Europe Salt & fresh water 5

Aquaculture engineering company UK Salt & fresh water 2

Environmental certification UK Salmon 2

Fish genetics academic expert UK Salt & fresh water 1

Other academic and industry experts Europe Salt & fresh water 4

Total 15


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nitrogen), NO2 (nitrate), BOD (Biochemical oxygen demand), COD (Chemical oxygen demand)) werecharacterised in terms of their amplitude and frequency. Although the efficiency of many treatment processesis concentration-dependent and therefore to some degree self-regulating, response times are highly variablee.g. oxygen deficits improve aerator efficiency immediately whilst the lag-phase for bacterial nitrificationadaptation in response to elevated ammonia concentration is much longer. Understanding such variability asinteracting limiting production factors now plays a critical role in system design and operation.

The on-going faith of RAS researchers and engineers in narrow technical solutions to problems of commercialviability going forward is illustrated by the strap-line: for better profits tomorrow of Recirc Today, a short lived1990s industry Journal.

2.2 Commercia l RAS performance in the UK

Despite considerable technical improvement, economic sustainability has remained elusive and is the greatestchallenge for long-term adoption of RAS for table fish grow-out. An objective historical assessment clearlyindicates that although the basic technology has now existed for over 60 years now, its application for

commercial table-fish production continues to exhibit a stop and start trajectory with many sunsetventurescollapsing after only 2-3 years of operation in sequential phases of adoption. Although new-starts, particularlythose for novel exotic species regularly make headline news in the aquaculture press, reasons for failures arepoorly documented, complicating objective assessments and recurrence of mistakes. This knowledge gap is aconsequence of sensitivity over costly failures, communication barriers associated with the fragmented natureof the nascent sector and potential conflicts of interest between technology providers and producers e.g.equipment providers are more likely to emphasise management problems rather than more fundamentaldesign or marketing constraints.

Factors contributing to a lack of profitability include vastly overestimated sales prices or growth rates, at other

times system design is fundamentally in error resulting in carrying capacities that are much lower thanoriginally projected. Often equipment is poorly specified or assembled rather than being inherently bad.Unforeseen shifts in critical energy and feed input costs have also contributed to failure.

In the UK, juvenile rather than table-fish production provides the most sustained example of commercialadoption, specifically for the production of juveniles in hatcheries and salmon smolts for cage/pond on-growing. Smolts constitute up to 20% of table-fish whole live farm-gate price, making them a high-valuecommodity; over three times the value of table-fish in weight terms. At the same-time their production in RASincurs a relatively small proportion of total salmon production costs. Consequently RAS have made aconsiderable contribution to increased smolt yields. Sustained adoption of RAS technology elsewhere has beenpredicated on farming higher-value species such as turbot, eel and sturgeon or production of value-added

products for niche markets e.g. production of live tilapia for the ethnic market in northern America.

Exotic tilapia (Oreochromis niloticus) was also one of the first candidate warm-water species for commercialscale table-fish culture in the UK. In the early 1990sa joint venture with Courtaulds textiles used waste heatthat was a by-product of the manufacturing process to reduce culture costs, selling their stock to Tescos.Other smaller-scale efforts were based on a similar integration strategy, for example using waste-heat and feedingredients from distillery operations. In addition to marketing difficulties these efforts eventually failed due toover-reliance on third-party provision of these services; Courtaulds began to charge for waste heat andmaintenance schedules for the primary production processes were prioritised over aquaculture

Thereafter other than for hobby-scale efforts, interest in warm-water table-fish production receded until early

in the new Millennium when a sequence of commercial start-ups for three key species occurred; tilapia,


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barramundi and sea bass (Fig. 1) which we will now consider in three case-studies. All were based on fully-recirculating RAS located in England and Wales close to large prospective urban markets. Whereas the lattertwo species were produced by just two sizeable individual joint ventures, the initial tilapia production figures(Fig 2) include contributions from multiple small-scale start-ups. Nearly all were adopters of a franchise-package offered by a British company called UK-tilapia based in Ely near Cambridge. This involved adoptersinvesting in turn-key production systems nominally capable of producing at least 100t/year designed and

installed by UK-tilapia, who also claimed to offer technical support, seed and feed provision and harvest buy-back options. All adopters were individual small-scale investors, mostly mixed-arable and livestock farmers inEastern England (Lincolnshire, Yorkshire and Durham) seeking diversification strategies for their businesses.Unfortunately UK-tilapias principle experience lay in seafood marketing rather than RAS design and operation(they had previously acquired a defunct RAS system with its own design problems near Ely). Consequentlydesigns were very basic, incorporating aerated fibreglass or concrete raceways, water and/or air heating,commercial drum-filters and self-designed/constructed up-welling biological filters. All culture treatment unitswere surface-mounted (i.e. no sumps or buried pipework) to minimise civil engineering costs but at theexpense of water-balancing ease and access for husbandry activities. There was also considerable variation inthe types and sizes of treatment units procured, and linked to this, apparently ad-hoc levels of modularisationin different installations. Low-cost design simplicity was predicated in part on the resilience of tilapia to turbid

water quality conditions. However although capable of survival in brown-water, growth performance issignificantly compromised. For these reasons the installed systems achieved less than half their designproduction capacity and most continued to fall far short of this figure even after significant remedialinvestment.

Figure 1: Number of UK RAS farms for table-fish production 2002-2013 (adapted from Jeffries et al

2010)

Of a total 29 RAS farms registered for grow-out production (i.e. excluding hatchery and smolt production)between 2000-2013, 18 (62%) were designed for tilapia production and most were UK Tilapia franchisees (Fig1). The first wave of seven adopters (2005-2006) ceased production within 2-3 years (under-reporting inFigure 1 is due to delays in formal reporting of closures). However in most cases movable plant was recycled

2000 2001 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013

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by UK Tilapia and passed on to successive waves of adopters in the region; thus the total number of adoptersover-estimates the amount of actual physical capital involved in this boom. The progressive south to northaxis of adoption along the English East coast suggests some degree of local communication and awareness ofthese problems. However, wider knowledge of the failures remained remarkably contained, perhaps reflectingthe insularity of these farming communities as well as the aforementioned sensitivity regarding commercialfailure.

Farmers also adopted a range of collective and individual strategies to bring the struggling businesses toprofitability with varying degrees of success. This included investment in third-party or often self-implementeddesign improvements. One farmer acquired refrigerated transport for value-added micro-marketing of hisproduce and potentially that of neighbouring farms, though ultimately had to sell the bulk of his harvest toBillingsgate market where it competed directly in the mainly ethnic market for low-cost imported tilapia.Three of the later-adopters came up with the most enduring survival strategy forming the Fish Company 4tocollectively market their product at the volumes and supply-regularity required by supermarkets; successfullycontracting with Morrisons and with M&J Seafoods who supply the restaurant sector. The total designcapacity of these farms was around 800t/yr most of this associated with one 500t farm, by far the largest of theboom. Faced with the same problems as other franchisees, the owner of this farm took the decision to

simultaneously re-design and significantly upscale the farm to produce more commercially realistic volumes forthe supermarket trade. Experienced professional management (from outside the UK) was also brought in andsteps taken to reduce production costs through energy-efficiencies through installation of solar panels andbiomass heating systems - also reinforcing a sustainable marketing message. Despite these efforts, sales-volumes came nowhere near the anticipated levels (Fig. 2) leading to the recent closures of two of the FishCompany farms leaving only one of the smaller units still trading at the time of this report.

Figure 2: UK RAS table-fish production 2002-2014 (adapted from Jeffries et al, 2010)

Note: 2011-2013 data and 2014 projections based on survey responses.

4http://www.cookingtilapia.co.uk/http://aquaculturedirectory.co.uk/lincolnshire-home-to-sustainably-farmed-tilapia/

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http://www.cookingtilapia.co.uk/http://www.cookingtilapia.co.uk/http://www.cookingtilapia.co.uk/http://www.cookingtilapia.co.uk/http://www.cookingtilapia.co.uk/


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Parallels of this history can be observed in the demise of New Forest Barramundi which operated for just overtwo years between 2006 and 2008. Located in a converted pizza factory in Lymington, Hampshire the farmoriginally designed to produce 400t/yr for the UK market had a modular design intended to allow rapidexpansion to an estimated 1,200t once markets were developed. Although farmed in freshwater barramundi(Lates calcifer) is a diadromous species also tolerant of brackish conditions. Due to its lack of bones, sweet-buttery taste and high Omega 3 fatty acid profile it is highly popular with consumers in its native Australia.

Unlike tilapia, no alternative sources of imports were established; i.e. there were no direct substitutes. Thechallenge of marketing a novel-species remained, though it shares many qualities with farmed Mediterraneansea bass already firmly established in the UK market (barramundi is also known as Asian sea bass). Fortunately,owners London-based Aquabella Group who raised 6.86 million in equity (87%) and debt (13%) capital5overthe life of the venture had considerable seafood marketing experience. They came to the market with firmcontracts through trial sales already established with Morrisons and Waitrose; Sainsbury's, FrancesIntermarche and wholesalers M&J Seafoods, Daily Fish, Macro cash & carry and Costco were subsequentlyadded. However, once again RAS production experience was lacking. An additional 4.58 million workingcapital raised on top of the original 2.28million investment was used for the remediation of design defects andto subsidise operational costs whilst the farm ran at significant under-capacity. Remediation included a new de-nitrification plant, improved sludge management processes and an ozone injection system all aimed at

improving the quality of the fishmost seriously an off-flavour taint associated with unfavourable biologicalactivity in the system. Aquabella also planned to shift its original focus of selling whole fish to value-addedgutted, filleted and smoked product. However, despite this considerable additional investment, it proveddifficult to recover the confidence of buyers once tainted fish had reached the market. Their troubles werefurther compounded by the impact of low demand during winter months. Ultimately sales fell far short oforiginal projections resulting in production costs more than twice the farm-gate price and post-tax losses of2.64 million on revenues of 0.46 million in the second year.

Our third case-study is Anglesey Aquaculture6located near Penmon on Anglesey, Wales, and the only marineRAS currently producing table-fish (seabass; Dicentrarchux labrax) for the UK market. This one farm hascontributed more than three quarters of all such production in every year since 2009 (Fig 2). The farm wasdeveloped by Selonda Aquaculture SA7, based in Greece, using water treatment technology supplied by thespecialist RAS engineering company IAT (International Aquaculture Technology) who had a proven track-record in the design and construction of intensive smolt RAS for Scottish salmon producers. Pilot trials withsea bass encouraged Selonada UK to commission a scaled-up RAS with a target production of 1,000t/yr. Thefarm produced its first fish (approx. 320t) in 2009. Financial difficulties of the parent company in Greece, linkedto the international debt-crisis, were the predominant factor in the farms underperformance and near closurein the following years. The company finally went into receivership in January 2012 with annual losses of 1.7 to1.8 million on a turnover of 1.9 to 2 million in 2009-2010 (the last two years of operation for whichaccounts are available (FAME 2013)).

Tethys Ocean B.V., the aquaculture division of Linnaeus Capital partners B.V. (Linnaeus) immediately acquiredthe assets, renaming the company Anglesey Aquaculture Ltd (AAL). Past production output has variedbetween 300 and 500t (Fig 2). Following recent management changes the company predicts production willincrease to between 600-650t in 2014 and aims to achieve full operational capacity in 2015. It is possible thecompany may then move into processing and value-added activities. No turnover figures are yet available forthe first year of operation although it reported a liquidity ratio (liquid assets/short-term liabilities) of 0.56(compared to a value of 0.11 for Selonda UK in 2010) and a QuiScore8(the likelihood of a company failure in

5http://www.proactiveinvestors.co.uk/companies/news/319/aquabella-is-struggling-with-barramundi-0319.html6http://www.angleseyaquaculture.com/index7

With financing also from the Saudi Arabian Jazan Development Company (http://www.jazadco.com.sa/en/activity.htm)8http://portal.solent.ac.uk/mobile/library/help/eresources/using-fame-database.aspx
http://www.proactiveinvestors.co.uk/companies/news/319/aquabella-is-struggling-with-barramundi-0319.htmlhttp://www.proactiveinvestors.co.uk/companies/news/319/aquabella-is-struggling-with-barramundi-0319.htmlhttp://www.proactiveinvestors.co.uk/companies/news/319/aquabella-is-struggling-with-barramundi-0319.htmlhttp://www.angleseyaquaculture.com/indexhttp://www.angleseyaquaculture.com/indexhttp://www.angleseyaquaculture.com/indexhttp://www.jazadco.com.sa/en/activity.htmhttp://www.jazadco.com.sa/en/activity.htmhttp://www.jazadco.com.sa/en/activity.htmhttp://portal.solent.ac.uk/mobile/library/help/eresources/using-fame-database.aspxhttp://portal.solent.ac.uk/mobile/library/help/eresources/using-fame-database.aspxhttp://portal.solent.ac.uk/mobile/library/help/eresources/using-fame-database.aspxhttp://portal.solent.ac.uk/mobile/library/help/eresources/using-fame-database.aspxhttp://www.jazadco.com.sa/en/activity.htmhttp://www.angleseyaquaculture.com/indexhttp://www.proactiveinvestors.co.uk/companies/news/319/aquabella-is-struggling-with-barramundi-0319.html


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the next twelve months) of 67 placing the company midway between normal and stable credit assessmentbands (there are 5 bands: secure, stable, normal, unstable, and high risk). The AAL venture is clearly pioneeringand has benefited from a longer incubation period than the other case-studies. In addition to its interests inmajor Mediterranean sea bass and sea bream cage aquaculture companies, Tethys Ocean B.V. also owns Israel-based company Grow Fish Anywhere9and expresses a strong belief in the future of land-based aquaculture. Inthe short-term at least, it therefore appears likely to be more committed and able to fund any on-going

liabilities than investors in the previous tilapia and barramundi case-studies.

In several of the case studies the original RAS design required modification and (sometimes substantial) furtherinvestment in light of operational experience. This in turn points to the bespoke nature of most of thesecommissions and the corresponding lack of standardised installations with proven track-records in the UK. Inthe case of AAL, problems were largely due to management and weak financial investment by the originaldevelopers. However, even in instances where sufficient funding was available to address the design problems,market factors clearly represented a further major underlying challenge to the economic sustainability of theseventures especially the barramundi project where the products sent to market were deemed unpalatable. To asignificant extent all the longer surviving ventures adopted similar market strategies targeting premium marketsectors through promotion of sustainability traits variously associated with RAS production and the target-

species (Table 2). AAL has reported on its improved growth rates and expects to achieve market size fish of450g in 50-60% of the time taken by cage fish in Greece or Turkey where winter temperatures suppressproduction. With continued improvements in management and understanding of RAS technology operationthe company is confident of further improvements in growth performance.

Many if not all these claims are entirely credible and consistent with growing pressure to buy and eatsustainable fish; however more problematical from an economic standpoint is the size of such premium marketsectors going forward and its potential for saturation should RAS production, or that of sustainable capturesubstitutes, increase significantly. For example tilapias were promoted as a sustainable alternative to cod butsustainably-certified cod (and pollack) harvests have since increased considerably. Although some top-endrestaurants have stocked tilapia the availability of low-cost imports also creates particular challenges inpositioning this species as a premium option. The largest existing demand comes from the ethnic market whichtend to buy on price and are happy w ith cheap frozen imports typically also of larger individual size. Asindicated earlier the (limited) success of tilapia RAS in North America is associated with a sizeable niche ethnicmarket for higher value live-fish sales.

Whilst sea bass (and sea bream) already tend to occupy a more premium niche they are also challenged by thescale of Mediterranean production. Despite apparent sustainability contradictions linked to localness and air-miles, Anglesey Aquaculture is targeting a much larger USA premium market as a key plank in its expansionstrategy. They have commenced regular air-freight deliveries to US-based Whole Foods Market which brandsitself as the worlds leading retailer of natural and organic foods with a global network of 340 stores (including

7 in the UK); the majority of seafood consumed in the U.S. is in restaurants. To this end, Anglesey Aquaculturehas also invested in achieving the responsibly farmed seafood standard developed by Whole Foods Marketand required of their seafood suppliers. The Dansish Langsand Laks salmon RAS venture (section 4.2) is alsoundergoing assessment against the same standard (as well as ASC certification) and seeking evaluation by theMonterey Bay Aquarium Seafood Watch program10, suggesting that it is also targeting the same USA segmentas part of its marketing strategy.

However reliance on overseas markets, particularly for fresh product with high transport costs also brings therisk of competition from local RAS start-ups, particularly for premium market segments. In fact the Whole

9

www.GrowFishAnywhere.com10http://www.langsandlaks.dk/
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Foods Market contract with Anglesey Aquaculture coincides with the failure of Local Ocean (Hudson, LakeMichigan, 2009-2013) a prior supplier of saltwater-RAS marine fish to the company (sea bream, sea bass,flounder and yellowtail)11. A patent lawsuit brought against the company by Tethys Oceans Israeli subsidiaryGrow Fish Anywhere contributed to Local Ocean financial difficulties. As with other highly capitalised start-ups ($13 million was invested in Local Ocean along with substantial government support) there is a strongpossibility that the business will see further reincarnations (e.g. processor Atlantic Cape Fisheries is

considering conversion to freshwater production)12

. Assuming progressive standardisation of technology andproduct quality in a maturing and economically viable RAS sector, there would also be decreasing scope todifferentiate similar species from different national RAS sectors other than by geographical indication. All threeUK case studies cited in this section do promote their regional location in their marketing mix (Table 2.)particular the sea bass and barramundi farms sited in idyllic protected areas. This could potentially beformalised as a protected geographical indication (TGI), but it is questionable whether this attribute alonewould secure a significant premium.

Table 2: Environmental and other quality product differentiation claims used by RAS producers to

target premium ethical markets

Marketing claims/ Unique SellingPoints (USPs)

The FishCompany13

(tilapia)

New ForrestBarramundi14

AngleseyAquaculture15

(sea bass)

Environmental

High water re-use rates Y Y

Energy minimisation/ recycling Y Y Y

Carbon neutrality/ reduced emission Y

Composting/ recycling of farm waste Y Y

Use of sustainably sourced feeds Y Y Y

No negative impact on wild fisheries Y Y

Disease biosecurity (& no antibiotics) Y YFood safety and quality Y

Use of hormone and GM free feeds Y Y

Product traceability Y Y

Highly fresh/ local & never frozen Y Y

Low food miles Y Y Y

Year round availability Y

Improved taste over same imported fish Y

Farmed species USP claims

Minerals P, Se, Vit B12

Fats High omega 3&6 High omega 3 2 High omega 3 2

11http://www.timesunion.com/business/article/Fish-gone-at-shuttered-Local-Ocean-farm-4863291.phphttp://www.timesunion.com/business/article/Fish-in-this-story-didn-t-get-away-4746595.phphttp://www.localoceans.com/12http://www.undercurrentnews.com/2013/09/26/group-in-talks-to-buy-us-based-zero-discharge-saltwater-fish-farm/13http://aquaculturedirectory.co.uk/lincolnshire-home-to-sustainably-farmed-tilapia/#sthash.HvhjVvV5.dpufhttp://www.cookingtilapia.co.uk/press-releases/Why_British_Tilapia_Makes_Sustainable_Sense.pdf14http://www.grocerytrader.co.uk/News/March_2008/G_aquabella.html15http://www.angleseyaquaculture.com/sustainabilityhttp://www.fish2fork.com/en-GB/news-index/2013/Fish-farm-overcomes-Greek-tragedy-to-produce-sustainable-sea-bass.aspxhttp://www.fishupdate.com/news/archivestory.php/aid/19684/Welsh_fish_farm_92s_green_credentials_are__perfect_fit_94_for_grocery_

chain.html
http://www.timesunion.com/business/article/Fish-gone-at-shuttered-Local-Ocean-farm-4863291.phphttp://www.timesunion.com/business/article/Fish-gone-at-shuttered-Local-Ocean-farm-4863291.phphttp://www.timesunion.com/business/article/Fish-in-this-story-didn-t-get-away-4746595.phphttp://www.localoceans.com/http://www.localoceans.com/http://www.undercurrentnews.com/2013/09/26/group-in-talks-to-buy-us-based-zero-discharge-saltwater-fish-farm/http://www.undercurrentnews.com/2013/09/26/group-in-talks-to-buy-us-based-zero-discharge-saltwater-fish-farm/http://aquaculturedirectory.co.uk/lincolnshire-home-to-sustainably-farmed-tilapia/#sthash.HvhjVvV5.dpufhttp://aquaculturedirectory.co.uk/lincolnshire-home-to-sustainably-farmed-tilapia/#sthash.HvhjVvV5.dpufhttp://aquaculturedirectory.co.uk/lincolnshire-home-to-sustainably-farmed-tilapia/#sthash.HvhjVvV5.dpufhttp://www.cookingtilapia.co.uk/press-releases/Why_British_Tilapia_Makes_Sustainable_Sense.pdfhttp://www.grocerytrader.co.uk/News/March_2008/G_aquabella.htmlhttp://www.grocerytrader.co.uk/News/March_2008/G_aquabella.htmlhttp://www.grocerytrader.co.uk/News/March_2008/G_aquabella.htmlhttp://www.angleseyaquaculture.com/sustainabilityhttp://www.angleseyaquaculture.com/sustainabilityhttp://www.angleseyaquaculture.com/sustainabilityhttp://www.fish2fork.com/en-GB/news-index/2013/Fish-farm-overcomes-Greek-tragedy-to-produce-sustainable-sea-bass.aspxhttp://www.fishupdate.com/news/archivestory.php/aid/19684/Welsh_fish_farm_92s_green_credentials_are__perfect_fit_94_for_grocery_chain.htmlhttp://www.fishupdate.com/news/archivestory.php/aid/19684/Welsh_fish_farm_92s_green_credentials_are__perfect_fit_94_for_grocery_chain.htmlhttp://www.fishupdate.com/news/archivestory.php/aid/19684/Welsh_fish_farm_92s_green_credentials_are__perfect_fit_94_for_grocery_chain.htmlhttp://www.fishupdate.com/news/archivestory.php/aid/19684/Welsh_fish_farm_92s_green_credentials_are__perfect_fit_94_for_grocery_chain.htmlhttp://www.fish2fork.com/en-GB/news-index/2013/Fish-farm-overcomes-Greek-tragedy-to-produce-sustainable-sea-bass.aspxhttp://www.angleseyaquaculture.com/sustainabilityhttp://www.grocerytrader.co.uk/News/March_2008/G_aquabella.htmlhttp://www.cookingtilapia.co.uk/press-releases/Why_British_Tilapia_Makes_Sustainable_Sense.pdfhttp://aquaculturedirectory.co.uk/lincolnshire-home-to-sustainably-farmed-tilapia/#sthash.HvhjVvV5.dpufhttp://www.undercurrentnews.com/2013/09/26/group-in-talks-to-buy-us-based-zero-discharge-saltwater-fish-farm/http://www.localoceans.com/http://www.timesunion.com/business/article/Fish-in-this-story-didn-t-get-away-4746595.phphttp://www.timesunion.com/business/article/Fish-gone-at-shuttered-Local-Ocean-farm-4863291.php


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Marketing claims/ Unique Selling

Points (USPs)

The Fish

Company13

(tilapia)

New Forrest

Barramundi14

Anglesey

Aquaculture15

(sea bass)

low in fats 1

Net protein producer Y

Third party certification

Organic PlannedAnimal welfare Claim Planned

MCS sustainable fish guide Y (1 rating) Y (1 rating)

Whole Foods Responsibly farmed Y

Exclusivity testimonials

High end supermarkets Y Y

High end restaurants Y Y

High end fishmongers Y

Geographical indication Y Y Y1Such claims are somewhat misleading as the ratio of PUFAs to saturated fatty-acids in tilapia is relatively lowhowever total fat levelsare also low making tilapia a lean protein source.

2 Feed composition can also have a significant effect on fatty-acid profiles.

2.3 Other region al commercia l RAS Examples

In this section we consider table-fish RAS grow-out ventures outwith the UK and the innovations that haveconferred longer-term economic success. Recent salmon start-ups are considered in detail in section 4.2.

Headquartered in Helmond, Holland, Fishion BV16was established around 2003 as a Joint Venture betweenZonAquafarming BV and Anova Food BV17, later becoming part the aquaculture division of Dutch agriculturalcompany the Van Rijsingen Groep. Fishion is the trade name of a supply chain from feed supply, farmers andprocessors to point of retail (as Anova branded products). Alliance partners co-ordinate production to closelymeet market requirements e.g. feed management and quality assurance are adjusted in real-time throughmonitoring and telemetry systems installed along the value-chain. The companys antecedents began RASproduction in 1985 successively producing a range of species including eel, sturgeon, salmon, tilapia and catfish.Fishion initially concentrated on tilapia production until around 8 years ago when focus began to shift to ahybrid catfish variety branded as Claresse18(a cross between two African catfish species: Heterobranchuslongifilisand Clarias gariepinus). Pure C. gariepinus has been farmed for over 30 years in Holland, being widelyadopted as a diversification strategy by intensive feed-lot pig farmers in response to increasingly strictenvironmental controls on nitrate-discharge from slurry-wastes. The already low farm-gate price of C.gariepinus subsequently collapsed due to over-supply. The Claresse hybridisation created advantageousproduction and post-harvest value-addition attributes including firm fillet texture, low bone content and most

importantly white-pinkish colouration. The latter attribute was particularly important in differentiating Claressefrom C. gariepinus which can yield a lower-value yellowish grey fillet. A further economic attraction lay in theability to farm catfish at extremely high stocking densities (>300 kg/m3) over a short grow-out period (from15g to 1400g in 7 months); far more favourable than the optimum level of 80kg/m3achievable for comparablypriced tilapia in the same RAS systems.

16http://www.fishion-aquaculture.com/en/fishion/http://www.ngva.org/data/Fishion%20-%20The%20Way%20Forward.pdf17

http://www.anovaseafood.com/page.asp?lStrLang=EN18http://claresse.eu/en/about.htm
http://www.fishion-aquaculture.com/en/fishion/http://www.fishion-aquaculture.com/en/fishion/http://www.fishion-aquaculture.com/en/fishion/http://www.ngva.org/data/Fishion%20-%20The%20Way%20Forward.pdfhttp://www.ngva.org/data/Fishion%20-%20The%20Way%20Forward.pdfhttp://www.anovaseafood.com/page.asp?lStrLang=ENhttp://www.anovaseafood.com/page.asp?lStrLang=ENhttp://www.anovaseafood.com/page.asp?lStrLang=ENhttp://claresse.eu/en/about.htmhttp://claresse.eu/en/about.htmhttp://claresse.eu/en/about.htmhttp://claresse.eu/en/about.htmhttp://www.anovaseafood.com/page.asp?lStrLang=ENhttp://www.ngva.org/data/Fishion%20-%20The%20Way%20Forward.pdfhttp://www.fishion-aquaculture.com/en/fishion/


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Factors contributing to the businesses longevity include efficient and proven RAS design, the range ofexperience and skills in the company and its business model. The directors included aquaculture graduateswith a broad technical and business knowledge. Production comes from a small number of nearby familybased-farms in Brabanteach requiring an investment of around Euro 2.5 million. The production systemswhich can accommodate catfish or tilapia with little modification were designed and built in cooperation withDanish company Inter Aqua19with a track record in RAS engineering. Considerable attention was given to

mitigation of off-flavour problems in the design phase (e.g. elimination of anoxic dead-spots that couldsupport problem bacteria) as well as husbandry and harvest requirements e.g. transport trailers with integralweighing mechanisms can directly access bays between culture and harvest transfer raceways. To meetenvironmental discharge limits, the farms also include de-nitrification systems developed in collaboration withWageningen University. This also results in extremely high recirculation levels and associated energyefficiencies; there is no requirement for water heating to an outdoor temperature of 0 C.

Previous research with tilapia RAS adopters in the UK (Young et al. 2010) clearly demonstrated very fewadopters, especially small-scale farmers had the necessary mix of production and marketing skills required toeffectively target premium markets. Fishion farms through a franchise deal similar in concept to that offered byUK tilapia, are clearly offering a credible combination of technical, fish-health and marketing support. This

example demonstrates that the franchise model can offer a sustainable route to adoption with the production-orientation of small-family farms becoming a virtue in their cooperative alliance. The company provides thefarms with feed and 12-15g catfish juveniles originating from breeding subsidiary Zon Aquafarming BV. Thecompany ultimately aims to use a 100% vegetarian diet; though around 30% and 18% of the total feed currentlyused for catfish and tilapia grow-out respectively is fishmeal and fish oil (supplied by Nutreco and Copens).

Processing is undertaken by Fishion affiliate Claresse Visverwerking BV. Stock is processed entirely in responseto confirmed demand (i.e. there is no storage on location) predominantly for distribution as chilled products inmodified atmosphere (MAP) packaging. The introduction of this processing-step corresponds with aprogressive shift from only 27% of production being destined for filleting in 2005 to 91% in 2009 on weeklyharvests of 11t and 86t Live Weight Equivalent (LWE) respectively (the balance being sold as whole roundproduct). Fishion distribution partner the ANOVA seafood group have a track record in product innovationand have taken a key role in positioning and promoting the Claresse brand. The company also uses many ofthe sustainability characteristics listed in Table 2 to differentiate their product - particularly from VietnamesePangasius catfish the main low-cost imported (frozen) fillet substitute for their chilled product.

High production efficiencies (Table 3) also means the company can profitably sell to lower-price marketsegments including institutional canteens as part of its market-mix. Figure 3 shows how continuous technicalinnovation progressively reduced unit costs for tilapia production (catfish data not available) against abackground of increasing energy and feed-input costs. Of particular note are the relatively high levels ofinefficiency during the first 8-9 years of operation (major gains followed in labour productivity, feed conversion

and energy efficiency, juvenile and financing costs). Secondly the high contribution of feed costs which will alsoincrease as a percentage of operational costs with increasing farm-scale, points to the need for engineering offeeds designed to optimise Feed Conversion Ratio (FCR) in RAS (Section 3.5.1). Labour (not shown) andenergy costs - which will also exhibit positive economies of scale with increasing production capacityfell toonly 5% and 23% of operational costs respectively in 2010. Increasing costs and poor energy efficiency was asignificant factor contributing to the failure of the recent UK tilapia start-ups.

19http://www.interaqua.dk/ras_plants.php
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Table 3: Comparison of production efficiency factors for catfish, tilapia and salmon in RAS

Company Langsand

Laks20

Fishion Fishion Traditional

RAS1

Open

Aquaculture

Species Atlanticsalmon

HybridAfrican catfish

Tilapia Tilapia Various

Culture medium Salt water Fresh water Fresh water Fresh water SW & FW

Grow-out weight range (kg) 0.125 to 4.5 0.12 to 1.4 0.12 to 0.8 0.12 to 0.8 VariousGrow-out time (months) 7 to 8 6 to 7 6 to 7

Annual farm productioncapacity (live-weight t)

1,0003 1600 600

Capital Investment ( mill) 4.074 2.5 2.5

Max Biomass Density (kg/m3) 85-100 >300 80Energy efficiency (kwh/kg)2 1.3 to 2.11 0.8 2 to 2.5Main pumps 0.97

Other system pumps etc 0.25

Cooling, denitrification, light,ventilation and other

0.89

Water efficiency (l/kg) 250 20 25 300 to 500 3,000 to30,000

Economic feed conversionefficiency

1.05 to 1.4


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3 RAS technology and range of application

3.1 Ration ale for RAS

RAS technology has been introduced to the aquaculture sector to enhance environmental control of landbased operations, increase security of marine and freshwater hatcheries and more recently for the ongrowingof seafood species to market size. The application of the technology to the latter sector is still in a state ofrapid evolution for a range of vertebrate and invertebrate speciesfreshwater and marine. RAS technologyfor fattening farms does have several advantages as well as significant challenges:

3.1.1 RAS Advantages

Longer average life of tanks and equipment (versus nets, boats) allowing for longer amortisation

periods. However, serious attention needs to be applied to building infrastructure for marine speciesdue to highly corrosive atmosphere that ensues when trying to maintain optimum temperatures in atemperate / northern climate.

Reduced dependency on antibiotics and therapeutants generate marketing advantage of high qualitysafe seafood.

Reduction of direct operational costs associated with feed, predator control and parasites.

Potentially eliminate release of parasites to recipient waters.

Risk reduction due to climatic factors, disease and parasite impacts provided the RAS design has fullytaken into account local climate, ambient air / water temperature conditions, incoming water

treatment and bio-security.

Head-starting species like salmon where it could be beneficial to lengthen the amount of time youngsalmon are raised in RAS before being transferred to cages. This reduces the amount of time the fishare exposed to the risks of the ocean growing environment, as well as potentially reducing totalproduction times by optimizing the growing conditions.

RAS production can promote versatility in terms of location for farming, proximity to market andconstruction on brown-field sites. However, they still need to be in close proximity to source watersupplies and consideration needs to be given to local water quality and aesthetics since RAS farmsresemble industrial buildings.

Enable production of a broad range of species irrespective of temperature requirements providedcosts of temperature control beyond ambient are energy efficient.

Enable secure production of non-endemic species.

Feed management is potentially greatly enhanced in RAS when feeding can be closely monitored over24h periods. The stable environment promotes consistent growth rates throughout the productioncycle to market sizeprovided the operator and RAS design has taken into account the diverse rangeof water quality management issues. Optimum environmental conditions promote excellent FCRswith some high value marine species achieving market size in 50% of time taken in sea cages.

The advantages of RAS in terms of feed management assumes the operator has the capability toaccurately control and record fish biomass, mortality rates and movements across the farm. Efficiency

in these tasks becomes increasingly important with increasing farm size.


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Due to increased growth rates and superior FCRs that can be secured in RAS farms energy savingsrelated to feed use may partially compensate for increased energy costs associated with pumping andwater purification.

Exposure of stock to stress on RAS farms can be reduced for some factors such as adverse weather,unfavourable temperature conditions, pollution incidents and predation. However, fish welfare can bereduced and exposure to stressful situations increased in relation to stocking density, chronic

exposure to poor water quality and associated metabolic by-products due to inadequate watertreatment technology or inexperienced management.

In the UK, economies of RAS farm size are important and the technology tends to favour higher valueseafood species rather than commodity species. This is a reflection of the relatively high labour andenergy costs in the UK. RAS operation allows full control over effluent waste, nutrient recycling intovalue added products with limited energy production being feasible. However, the carbon footprintgenerated by a closed containment facility drawing electricity, pumping in water, filtering waste,among other actions, is significant. The source of the electricity, for example, hydro-generated orcoal-generated, would play a major factor in the perceived sustainability of RAS. That said, a full life-cycle analysis of both cage aquaculture production and land-based RAS is needed. Dr Andrew Wright(Quoted in Weston, 2013) notes that no accurate accounting has been done to measure the methanereleases caused by the decomposition of the wastes that accumulate on the ocean floor beneath opennet salmon farms.

3.1.2 Challenges of RAS technology

Lack of suitably experienced RAS managers and operators. Former cage or hatchery managers are notnecessarily sufficiently well qualified to operate commercial scale RAS fattening farms withoutminimum 6-10 months training on the job. Poor awareness in terms of the broad range of waterquality variables that require 24h in-line monitoringespecially in marine RAS.

While RAS farms enable operators to avoid any release of particulate solid or dissolved nutrientwaste into recipient waters its questionable how many investors take this issue seriously orappreciate the costs of implementing waste management into the production programme.

Investors in RAS technology, even those with aquaculture experience, generally know little aboutwater quality control, sea water chemistry and waste management at the industrial scale. Equally, RAStechnology suppliers often know little about aquaculture and / or have a weak biological background.

Investors fail to prepare adequately when identifying an appropriate RAS technology packagehencethe large number of commercial failures

Conclusion about economic viability of a RAS project is often based on assumptions and variablesrelated to expected market price, utilization of the waste stream, product quality, optimal andmaximum densities achievable, energy costs and costs relating to depreciation and interest on loans.Some of these criteria are subject to change and where assumptions are based solely on small pilot orresearch projects then even greater caution is required.

Production of species preferring warmer water (20-25oC) can be advantageous both from a growthrate standpoint but also in terms of energy conservation. Maintaining optimum water temperaturesfor species like sea bass or bream, as opposed to species like turbot or halibut, is likely to be less


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energy demanding in the UK provided the farm buildings are properly insulated 21. Alternatively, ifreliable, consistent low cost methods of cooling can be assured then the options for farming a rangeof temperate and cold water species alongside higher value Mediterranean or even tropical speciesare broadened. Experienced technicians to work with these species will need to be recruited fromabroad.

Species selection for UK RAS production is a critical issue. Irrespective of sustainability arguments for

RAS production, the farm still needs to make a profit. Production of a commodity species in RASwhich has to compete with the same product either imported or farmed using a lower productioncost method requires serious risk assessment. The development of commercial scale marine RAS inthe UK has focussed on the higher value seafood species such as European sea bass. However, thisproduction still has to compete with large volumes of low priced imported product from theMediterranean even though the latter is of inferior quality and not necessarily farmed with the samedegree of sustainability.

Ironically, superior prices can be secured in overseas markets for UK RAS farmed sea bass which iscounter to the argument of building RAS close to the domestic market. Once effective RASproduction becomes more widely deployed then options for the export of UK RAS production

becomes more restricted and large scale farms producing in excess of 400-500 tonnes per annum willstruggle to secure a premium price in the UK market for their entire annual production unless theycan dominate the market with volume production and diversified value added products.

Dependency on securing a premium price for a RAS farmed product justified by sustainability criteriamay not always hold true. This is particularly so in terms of energy demand, energy source andassociated carbon footprint.

Reducing operational costs of RAS farms through utilisation of farm waste for value added products isperfectly feasible but is often over-played by developers. RAS farm effluent takes the form of a mobilesludge and dissolved nutrient streams which can be readily recycled into value added products such ascomposts, micro-algae and polychaete worms. However, the argument that parallel production ofpolychaete worms in RAS farm waste would be sufficient to totally substitute fish meal in feeds forthe farm requires very close scrutiny - even if the polychaetes were nutritionally adequate as fish mealsubstitutes. The management of RAS farm sludge is a very real issue which few developers seem toproperly appreciate at the outset of the project.

The utilisation of RAS farm waste for on-site energy production is also feasible and the potentialcontribution in trial studies indicates this approach could be useful (Mirzoyan et et al., 2008; 2010).However, the investment in anaerobic digesters and equipment for conversion of gases to usableenergy needs to be carefully balanced against the potential savings in power consumption. EUresearch into the potential of RAS farm waste as an energy source is currently underway (BiFFio -FP7: Research for the benefit of SME-AG) but this programme is focussed on the contribution of RAS

aquaculture waste to energy production off-site and in combination with the larger volumes ofagricultural waste. This approach will not necessarily benefit the RAS farm as it may still incur costs totransport the waste off-site under license. Ideally, energy generation utilising RAS farm waste shouldbe implemented on site and this option should become increasingly attractive with larger farm sizes.

21

This is due to the heat produced within RAS which can be conserved for warmer water species, but will require cooling for cold waterspecies


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3.2 RAS typo logy and design cons iderat ions

The basic principle of RAS is to re-use water though the application of suitable treatment processes. There canbe varying degrees of water reuse depending on the system design. A simple flow-through fish farm where awater supply is diverted through ponds or tanks and then discharged has no water re-use. If aeration oroxygenation is added to the ponds or tanks there is already some water re-use as more fish can be produced

using the same water flow. However, recirculation implies treatment of some or all of the discharge water andreturning this to the fish rearing system as shown in the figure below.

Figure 4: Basic concept of a recirculation system

Considering the above figure, a key design parameter is the ratio of recycled water to waste water (morecommonly quoted as percentage of recycled water in the fish tank inflow water). A useful boost to farmproductivity can be achieved by recycling say 50% of the water flow and using basic solids removal and re-aeration technology for treatment. As the ratio of recycled to new water increases, more sophisticated andefficient treatment processes are required with implications for capital and operating costs. If the drivers forusing RAS include biosecurity, full control over environmental conditions or minimal nutrient discharge to

nearby waters, then a high ratio of recirculated to replacement water is usually required (at least 95-99%).

A related measure of water re-use is the water replacement rate, which is usually quoted in percentage of thesystem volume changed per day. If for instance a system has a 95% recirculated flow at a rate that effectivelyreplaces the full volume in the tanks once per hour; then over the course of 24 hours 1.2 times the volume ofthe tanks will be needed in new inflow water (120% replacement rate). A 5% per day replacement rate on thesame system would translate to 99.8% of the tank discharge being treated and returned to the inflow. Theinverse of water replacement rate is the water retention rate, so for a replacement rate of 5% per day, theretention of water within the system would be 95%. Somewhat confusingly, this is usually referred to as thePercent Recycle (Timmons et. al. 2001)particularly in North American literature. This makes rather moresense when the design of recirculated systems is considered, as very few employ a simple circuit as shown in

Figure 4. In practice, few systems achieve greater than 98% recycle as water is lost from the system mainlythrough solids removal. Many experts in this area consider the term RAS to only apply to systems with greaterthan 90% recycle (less than 10% water replacement per day).

The essential functions of a RAS are:

Provide a suitable physical environment for the fish with respect to space, water flow conditions,stock density

Protect the stock from infection by disease agents Provide for the physiological needs of the fish (mainly oxygen and nutrition) Remove metabolic wastes from the fish (notably faeces, ammonia and carbon dioxide) Remove waste feed and breakdown products (solid and dissolved organic compounds) Maintain temperature and water chemistry parameters within acceptable limits


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The latter target can be difficult to achieve in practice, as water quality parameters interact with each other incomplex ways, especially in seawater. Furthermore, the operating conditions of the system are changing on analmost daily basis as fish grow, diets and feed rates change, and harvesting takes place.

The most common processes in RAS are shown in the diagram below.

Figure 5: Common unit processes used in recirculating aquaculture production systems (adapted from

Losordo et al, 1998)

Examples of technologies used in RAS are listed in Table 4

Table 4: Technologies used in high rate Recirculated Aquaculture Systems

Water quality factors to be

controlledExample technologies employed

Suspended solids Sedimentation (for coarser particles)Self-cleaning screen filtersPressurised sand filtersBag and cartridge filters (for very fine solids)Foam fractionation (marine systems)

Ammonia Biofiltration converts ammonia to nitrite and then nitrate.

Nitrate Denitrification (or dilution in lower rate recycle systems with lesssensitive stock)

Phosphate Chemical precipitation or biological processes in combination withdenitritfication

Dissolved organic compounds

(mainly carbon)BiofiltrationFoam fractionation (marine systems)Ozonation

Carbon dioxide and nitrogen gas Degassinge.g. using vacuum degassers or forced air packedcolumn trickle filters

Oxygen Aeration at low saturation concentrations and oxygen injection athigh saturation concentrations


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Water quality factors to be

controlledExample technologies employed

Temperature Heat exchangers with gas fired boilers or other appropriate heatsource or chillers for cooling; Heat pumps

Pathogens UV lampsOzone (+ deozonation using activated carbon and/or UV)

pH Chemical dosing (e.g. sodium bicarbonate);Calcium or magnesium compound filters;(Denitrification filters counteract alkalinity consumption)

Chlorine (e.g. if using a chlorinated

supply)Activated charcoalDegassing

Metals (e.g. iron, manganese in

supply water)Special absorption filters;Oxidation and/or chemical precipitation and filtration

Salinity Adjust with freshwater or seawater addition

Modern RAS tend to employ multiple treatment loops as it may not be necessary to treat all the water on

every cycle through the tanks and for some processes may be advantageous to prolong residence time in theequipment (e.g. ozonation). On the other hand, pre-treatment may be desirable for other processes, e.g. UV ismore effective after fine suspended solids removal. Optimising the design with respect to minimising pumpingcosts and providing effective treatment and control can be a major challenge.

In most cases it will be necessary to use a separate water treatment system for incoming water and probablytwo or more separate systems for the farm itself. Whilst there are clearly scale related savings from using justone set of treatment equipment, this creates a greater risk of total loss if something should go wrong. It canalso be desirable from the management perspective to have greater flexibility in operations and isolationbetween stocks. The major design parameters for RAS are shown in the table below.

Table 5: Major design parameters for RAS

Parameter Comments

Salinity This will depend on the requirements of the species, but marine systems haveinherently more complex water chemistry and less efficient biofiltration.However, foam fractionation is a useful treatment only available in seawater.

Biomass & feed rate These will generally be related, but the quantity of feed introduced to thesystem each day is generally the most important factor for system sizing.Further considerations are the variation in biomass and feed and in somecircumstances, changes to the composition of the feed during the culturecycle

Stock density This is highly dependent on species, size range and other factors such aswater quality, tank dimensions and perhaps water flow dynamics. Higherstocking densities generally imply more efficient utilisation of tank volume andoverall facilities

Production plan The system is designed around the production plan which determines theexpected length of time batches of fish will be in specific tanks, when they willbe graded and moved to other tanks and when they will be harvested ormoved out of the system. The use of multiple batches involving staggeredstocking and harvesting schedules is normal in RAS to optimise use ofresources and maintain reasonably stable biomass.

Water flow rates These may be calculated in relation to biomass so as to provide a consistent

replenishment of water per minute per kg or stock. However changes in


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Parameter Comments

volumetric flow rate also normally changes water velocities, which can changeother parameters such as solids removal and energy expenditure by the fish.Consideration of water velocities in relation to body length can be a usefuldesign parameter.

Temperature control and

energy efficiency

Maintaining optimum temperatures in RAS can be challenging, particularly

where ambient temperatures vary seasonally, or are substantially different tothe needs of the stock. The entire facility needs to be designed to minimiseenergy requirements for heating or cooling. Similarly, the energy required forpumping and gas exchange is probably the second major cost factor afterfeed and therefore careful design to minimise requirements and maximiseefficiency is essential (e.g. through minimising pumping head, selecting widebore pipes and efficient pumps etc).

Feed system This will be specified based on volumes and feed rates required, the degree ofautomation and appropriate methods of (bulk) feed handling and storage.

Biosecurity A risk assessment needs to be carried out that considers factors such asspecies, potential pathogens, disease susceptibility, location and potentialroutes of infection. This will lead to decisions on disinfection and otherbiosecurity measures.

Water quality targets Target water quality criteria need to be set at the design stage to help defineperformance requirements for treatment equipment. Typical parametersinclude suspended solids, dissolved oxygen and carbon dioxide, ammonia,nitrite and nitrate, pH, alkalinity, salinity and temperature. Indicators ofdissolved organic matter such as BOD and DOC or turbidity and colourationmight also be set.

Monitoring & control Requirements for system monitoring will be based on design the criteria andwater quality targets set, together with a risk assessment of potential points

of system failure. Computerised control systems can both help to reducelabour requirements and improve response to out of range conditions.

Fish movement and

gradingDesigns should ensure that basic fish husbandry operations such as stockingtanks, splitting and grading stocks, moving to different tanks, interim and finalharvests, vaccination and disease treatments can all be performed as efficientlyas possible. Fish pumps are commonly used, but there are implications fortank design and layout and building design. Consideration must also be givento the removal and management of mortalities

Waste treatment and

disposalThe major waste stream from RAS is organic solids which frequently needdewatering and other treatment prior to disposal or utilisation elsewhere

3.3 Current examples

Some examples of recirculation configurations are shown below. These are taken from documents or websitesmade public by the manufacturers or researchers concerned. No endorsement of specific approaches ortechnologies is implied through the selection of examples.

The first example is a RAS for salmon smolt production marketed by the Norwegian company Akva (through abuy-out of the Danish firm Uni-Aqua). This features a double loop which treats the full recycled flow with


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solids filtration, UV disinfection and degassing, with only a proportion of the flow treated through moving bedbio-reactors (MBBR). Oxygenation is carried out at the tanks using cone injectors.

Figure 6: Schematic of a modern RAS suitable for salmonids from AKVA22

A second and fairly similar example is takenfrom the Freshwater Institute in the USA,which has influenced many developments inrecent years. It adds radial flow settlers to the

solids removal process and uses fluidised sandbiofilters rather than moving plastic media. Aswith the Akva system, a partial (60% flow) ispassed through the biofilters.

Figure 7: Schematic of RAS design from the Freshwater Institute, Virginia USA23(experimental scale)

22

http://www.akvagroup.com/products/land-based-aquaculture/recirculation-systems)23http://0301.nccdn.net/1_5/2ec/317/07d/06-Summerfelt_Update-on-growout-trials.pdf
http://www.akvagroup.com/products/land-based-aquaculture/recirculation-systemshttp://www.akvagroup.com/products/land-based-aquaculture/recirculation-systemshttp://www.akvagroup.com/products/land-based-aquaculture/recirculation-systemshttp://0301.nccdn.net/1_5/2ec/317/07d/06-Summerfelt_Update-on-growout-trials.pdfhttp://0301.nccdn.net/1_5/2ec/317/07d/06-Summerfelt_Update-on-growout-trials.pdfhttp://0301.nccdn.net/1_5/2ec/317/07d/06-Summerfelt_Update-on-growout-trials.pdfhttp://0301.nccdn.net/1_5/2ec/317/07d/06-Summerfelt_Update-on-growout-trials.pdfhttp://www.akvagroup.com/products/land-based-aquaculture/recirculation-systems


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The third example is an experimental scale marine RAS designed at the Centre of Marine Biotechnology,University of Maryland, USA. The system components include: (A) 0.3 m3microscreen drum filter, (B) 0.4 m3pump reservoir, (C) 0.9 m3CO2stripper, (D) 1.5 m

3protein skimmer, (E) 8 m3nitrifying moving bed

bioreactor (MBB), (F) 1 m3

low head oxygenator, (G) 0.6 m3

pump reservoir, (H) 0.15 m3

conical sludgecollection tank, (I) 0.5 m3sludge digestion tank, (J) 3 m3denammox fixed-bed up-flow biofilter, (K) 0.02 m3biogas reactor with gas collection. Tank water was used to backwash organic solids from the microscreendrum filter (A).

Figure 8: Schematic of RAS design from the Centre of Marine Biotechnology, University of Maryland,

USA24

A somewhat similar system is used by Aquatec-Solutions, a Danish RAS technology supplier:

Figure 9: Schematic of RAS design from Aquatec-solutions in Denmark25

24http://www.interfishexpert.com/environmentally-sustainable-land-based-marine-aquaculture/
http://www.interfishexpert.com/environmentally-sustainable-land-based-marine-aquaculture/http://www.interfishexpert.com/environmentally-sustainable-land-based-marine-aquaculture/http://www.interfishexpert.com/environmentally-sustainable-land-based-marine-aquaculture/http://www.interfishexpert.com/environmentally-sustainable-land-based-marine-aquaculture/


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The inclusion of an anaerobic circuit complicates the design, but with potential benefits discussed below.

3.4 Bios ecuri ty and disease issues in RAS

3.4.1 General issues and approaches to biosecurityPublic demand for reduced impact on the environment in an industry where the market for seafood continuesto expand is pushing the aquaculture sector to develop new intensive technologies and approaches totraceable and sustainable seafood production. RAS are expected to reduce the incidence of disease outbreaks,lower dependency on medication and promote more stable production aimed at meeting the demands of theseafood market.

Biosecurity includes any company policy and procedures used on a farm that reduce the risk of pathogenintroduction or spread through the facility if they are introduced. Delabbio et al. (2004) surveyed the troutsector in the US and showed that RAS biosecurity was not homogenous. Overall, inexpensive and low-techbiosecurity practices were utilized with the most common limited to record-keeping and dead fish collection.

66% of facilities reported prophylactic use of chemicals on fish while 81% reported therapeutic use.Quarantine procedures on incoming fish and/or eggs were commonly employed in RAS facilities, with use of anisolation area occurring more frequently (83%) than use of an isolated water supply (66%). These examples donot represent the type of RAS technology that is relevant to enhancing seafood production or diversificationwithin the UK.

One of the primary advantages of RAS technology is that it provides the farmer with the opportunity toreduce disease outbreaks and actually eliminate some diseases altogether. However, while RAS can createoptimum conditions for fish culture, inferior designs may inadvertently provide favorable conditions for diseaseoutbreaks or the reproduction of opportunistic pathogens (Delabbio et al., 2004; Timmons et al., 2002).Where pathogens have already gained access to the RAS their potential impact on the stock can be influencedby the quality of the system design but equally importantly the knowledge and experience of the RAS manager.In RAS farms where the farmer has incomplete control over the ambient environmental conditions, such astrout RAS located outside with weak biosecurity or in non-insulated buildings, the RAS system is exposed tovariable environmental conditions (variable temperature, ammonia removal rates) which leads to systeminstability, favouring disease outbreak.

dOrbcastel et al. (2009a,b) evaluated RAS trout farms and one of their main conclusions was that thesedimentation system showed a good but highly variable removal efficiency (6028%) such that the remainingsuspended solids are circulated and degraded in the system. This results in sedimentation areas i

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